As high temperatures and heavy rainfall continue to make conditions ideal for algae blooms, those who live near the St. Lucie and Caloosahatchee estuaries are calling out for relief from freshwater releases from Lake Okeechobee. So-called “emergency estuary protection wells” could offer relief.
According to Robert Verrastro, South Florida Water Management District principal hydrogeologist, the emergency wells would use deep injection well (DIW) technology to move excess stormwater 3,000 feet underground into the “boulder zone” to help protect the Caloosahatchee and St. Lucie estuaries from damaging flood-control discharges from the lake.
Mr. Verrastro said the technology has been around for the past 50 years throughout South Florida, with more than 200 DIWs operating dependably and quietly. Okeechobee Utility uses a DIW for part of its wastewater disposal, when rainfall is too heavy for the sprayfields to accommodate.
These wells would be a vertical option to disposing of water that would otherwise go to tide through the St. Lucie and Caloosahatchee estuaries, he explained.
When flood conditions give water managers no choice but to send freshwater to tide, instead of bombing the coastal estuaries with excess freshwater, DIWs could send the water to tide by pumping it 3,000 feet underground into the boulder zone.
These wells have a very high capacity on the order of 15 million gallons a day of water, he explained.
The district is considering a plan to install 40 to 80 emergency estuary protection wells north of Lake Okeechobee. These wells could reduce the need to send water east or west to tide, and give the coastal estuaries relief from lake discharges while the Comprehensive Everglades Restoration Plan projects are under construction.
The CERP projects will accommodate about 80 percent of the current flow to tide, he explained.
Mr. Verrastro said even after CERP is complete, the wells could still be used to prevent harmful freshwater flows to the coastal estuaries during periods of high rainfall.
The water SFWMD is considering putting into these wells is only water that would otherwise go to tide, he said.
CERP also includes Aquifer Storage and Recovery (ASR) wells, which allow water to be recovered when needed. The ASR wells cannot accept water quickly enough to handle the rapid flow into the lake when there is heavy rainfall north of the Big O.
Mr. Verrastro said SFWMD is conducting studies to determine the right number of wells and the best places to put the DIWs.
DIWs can be constructed on right-of-way SFWMD already owns, he said, so construction would not have to wait for land acquisition.
“It’s going to take a year or two for us to get the program underway,” he said.
“Over the next few years, these wells could be constructed to give the estuaries some relief from the high volume harmful discharges of freshwater from the lake,” he said.
For a video about emergency estuary projection wells, or more on SFWMD’s efforts to manage high water, go online to sfwmd.gov.